I'm no expert on channels but you really should get rid of those median lines and work only with the segments of intersecting channel lines where the upper trendline of one channel meets the lower trendline of the other channel. This will form a so-called triangle in the shape of "<" or ">". I dunno about you, but this was an eye-opener for me.
Can we talk? Forget your lines. See the 45 degree lines up and down placed to the right each time. That is channel change.